Table 6.

Significance of the association of myelotoxicity with TPMT or ITPA variant genotypes in ALL patients treated with 6-MP (n = 75 samples in 19 ALL subjects)^*

Genotype	Leucopenia (n = 29)	Neutropenia (n = 22)	Thrombocytopenia (n = 11)
TPMT*3 heterozygote	0.045	0.006	0.336
ITPA C94→A heterozygote	0.342	1.000	0.582
ITPA IVS2+21A→C mutant†	1.000	1.000	0.012

^*Numbers represent P-values for the corresponding association adjusted as per the Bonferroni justification for multiple testing.

^†Mutant refers to any mutant (homozygote or heterozygote). TPMT, thiopurine S-methyl transferase; ITPA, inosine triphosphatase; ALL, acute lymphoblastic leukaemia.